苹果液泡铁离子转运蛋白基因家族的鉴定与表达分析

Identification and Expression Analysis of the Vacuolar Iron Transporter Gene Family in Apple

液泡铁离子转运蛋白(vacuolar iron transporter,VIT)参与铁的储存和运输,对植物光合作用、固氮、呼吸、DNA和激素合成有重要作用。本研究中鉴定了苹果全基因组的9个VIT基因,通过系统发育分析其进化关系,表明苹果VIT蛋白与拟南芥进化关系较近。染色体定位显示9个VIT基因分布在7条染色体上,VIT基因的启动子区域富含光反应、植物激素调控和启动子相关顺式作用元件。表达谱分析显示VIT基因在花和果实中的表达量相对较高。此外,对MdVIT家族进行蛋白理化性质、String互作网络和基因结构等分析,表明苹果VIT家族扩增的主要因素是串联重复和片段复制,与苹果VIT蛋白互作的主要蛋白是阳离子共转运蛋白(XP_008372221.1和XP_008383418.1)。qRT-PCR分析结果表明:在2000μmol·L^(-1)FeSO_(4)·7H_(2)O(高铁)处理的‘M26’苹果砧木苗中,苹果VIT家族基因在不同组织的表达中存在差异,6 h后,MdVIT4在茎中的相对表达量最高,是对照的237倍。24 h后,MdVIT1和MdVIT2在叶片中的相对表达量与对照相比呈现上调表达,分别是对照的6.6倍和12.0倍。综上,基因MdVIT1、MdVIT2和MdVIT4可能与植物耐铁胁迫有密切关系,为苹果逆境胁迫机制研究提供参考。

Vacuolar iron transporter(VIT)is involved in iron storage and transport,it plays important roles in plant photosynthesis,nitrogen fixation,respiration,DNA and hormone synthesis.In this study,nine apple VIT genes were identified,and the phylogenetic relationship of these genes was analyzed by phylogeny,the results showed that the VIT protein of apple was closely related to the evolution of Arabidopsis thaliana.Chromosome mapping showed that nine VIT genes are distributed on seven chromosomes,bioinformatic analysis of VIT genes promoter region showed many cis-elements related to environmental stresses,photoresponse and plant hormone response.Expression profile analysis showed that the expression of VIT gene was relatively high in flowers and fruits.In addition,the physical and chemical properties,protein interaction network and gene structure of MdVIT family were analyzed,the results showed that the main factors for VIT family amplification in apple were tandem duplication and segmental duplication,cationic co-transporters(XP_008372221.1 and XP_008383418.1)were mainly involved in the interaction of VIT proteins in apple.The qRT-PCR analysis showed that the expression levels of MdVIT1 and MdVIT2 in leaves of‘M26’apple rootstock seedlings treated with 2000μmol·L^(-1) FeSO_(4)·7H_(2)O for 24 h were 6.6 and 12 times higher than those of the control.After 6 h treatment with 2000μmol·L^(-1)FeSO_(4)·7H_(2)O,the relative expression level of MdVIT4 showed in the stem was the highest,which was 237 times higher than that of the control.Taken together,among the characterized apple VIT genes MdVIT1,MdVIT2 and MdVIT4 were speculated closely related to iron stress in apple,which provide useful information for further study the mechanisms of metal iron caused stress in apple.